液体模塑成型工艺二维径向非饱和流动数值模拟

通过引入沉浸函数建立了双尺度多孔介质非饱和流动模型，并采用有限元/控制体积法实现了恒压及恒流注射条件下液体模塑成型（LCM）工艺二维径向非饱和流动的数值模拟，得到了不同注射条件下纤维织物内的压力场分布及半饱和区域长度随时间的变化规律，并将双尺度非饱和理论结果与单尺度饱和理论结果进行对比。结果表明：非饱和流动过程中，半饱和区域内的压力和压力梯度明显下降；半饱和区域长度随时间逐渐增加随后保持稳定，当流动前沿到达出口后半饱和区域长度开始逐渐减小；当两个主方向渗透率不同时，沿主方向半饱和区域长度也不同，渗透率越大该方向的半饱和区域长度也越大，纤维织物完全浸润时间取决于较小的渗透率。研究结果对合理预测树脂填充过程中压力分布及纤维预制件的浸润具有指导意义。

Numerical simulation of 2-dimensional radial unsaturated flow in liquid composite molding processes

A dual-scale unsaturated flow model was established by introducing the sink function, and the finite element/control volume method was employed to simulate numerically 2-dimensional radial flow in liquid composite molding(LCM) processes under the conditions of constant pressure and constant flow. The pressure distribution and time-varying resin flow front were obtained and compared with the results of theoretical prediction of single-scale model. The simulation results show that during unsaturated flow process, pressure and pressure gradient drop significantly in the unsaturated region; the length of unsaturated region increases firstly and thenkeeps constant, when the saturated flow front reaches the exit, the length begins to decrease; when there is a difference in permeability of two principal direction, the length of unsaturation region in the direction of higher permeability is longer and the time to completely infiltrate the fabric depends on the smaller permeability. The research results have significance to reasonably predict the pressure distribution and the infiltration of the fiber preform in the resin filling process.